Apparatus and method for generating an acoustic radiation pattern

Abstract

Disclosed are an apparatus and method for creating an acoustic radiation pattern, which may improve sound focusing performance to a target position. The acoustic radiation pattern creating apparatus may process an input signal which may be output through a speaker array in a room such that at least one vertical-directional reflected wave component of the input signal may overlap a direct sound of the input signal at the target position. Then, the acoustic radiation pattern creating apparatus may replicate the processed input signal by the number of output channels of the speaker array, and may process the replicated input signals such that the replicated input signals may form a predetermined radiation pattern in a horizontal direction in the room when the replicated input signals are output through the speaker array.

What is claimed is: 
     
       1. An apparatus for creating an acoustic radiation pattern using a speaker array, the apparatus comprising:
 a reflected wave overlapping filter configured to generate a processed signal by processing an input signal; 
 a replicator configured to generate replicated signals by replicating the processed signal by a number of output channels of the speaker array; and 
 a focusing filter configured to generate acoustic signals by processing the replicated signals such that the acoustic signals form a predetermined radiation pattern in a horizontal direction in a room when output through the speaker array, wherein 
 the reflected wave overlapping filter processes the input signal using gain and delay values of one or more vertically-directional reflected wave components extracted from impulse responses of a measurement signal measured at a target location, such that a vertically-directional reflected wave component and direct sound of the acoustic signals output by the speaker array overlap at the target position. 
 
     
     
       2. The apparatus of  claim 1 , wherein the reflected wave overlapping filter is created by performing time-reversal on the one or more extracted vertically-directional reflected wave components. 
     
     
       3. The apparatus of  claim 2 , wherein the reflected wave overlapping filter is created using the gain and delay values which are extracted from particular impulse responses measured in a predetermined early reflection period among the measured impulse responses of the measurement signal. 
     
     
       4. The apparatus of  claim 3 , wherein the reflection wave overlapping filter comprises:
 a distributor configured to:
 replicate the input signal by the number of the one or more vertically-directional reflected wave components extracted from the measured impulse responses to generate replicated input signals; and 
 distribute the replicated input signals; 
 
 an applying unit configured to apply the gain and delay values of the one or more extracted vertically-directional reflected wave components to the distributed input signals; and 
 a summing unit configured to sum signals resulting from applying the gain and delay values to the distributed input signals. 
 
     
     
       5. The apparatus of  claim 3 , wherein the reflection wave overlapping filter comprises a Finite Impulse Response (FIR) filter designed using the gain and delay values of the one or more extracted vertically-directional reflected wave components. 
     
     
       6. An apparatus for creating an acoustic radiation pattern using a speaker array, the apparatus comprising:
 a replicator configured to generate replicated signals by replicating an input signal by a number of output channels of a speaker array; and 
 a filtering unit configured to process the replicated signals and thereby generate acoustic signals that, when output by the speaker array, have a predetermined radiation pattern in a horizontal direction within a room and a vertically-directional reflected wave component and direct sound that overlap at a target position, wherein 
 the filtering unit processes the replicated signals by applying gain and delay values of one or more vertically-directional reflected wave components extracted from impulse responses of a measurement signal measured at the target location. 
 
     
     
       7. The apparatus of  claim 6 , wherein the filtering unit comprises a reflected wave overlapping filter created by performing time-reversal on the one or more extracted vertically-directional reflected wave components. 
     
     
       8. The apparatus of  claim 7 , wherein the reflected wave overlapping filter is created using the gain and delay values which are extracted from particular impulse responses measured in a predetermined early reflection period among the measured impulse responses. 
     
     
       9. A method of creating an acoustic radiation pattern using a speaker array, the method comprising:
 primarily filtering, sing a reflected wave overlapping filter, an input signal to generate a processed signal; 
 replicating the processed signal by a number of output channels of the speaker array to generate replicated signals; and 
 secondarily filtering, using a focusing filter, the replicated signals so as to generate acoustic signals that, when output by a speaker array, form a predetermined radiation pattern in a horizontal direction in a room, wherein 
 the reflected wave overlapping filter processes the input signal using gain and delay values of one or more vertically-directional reflected wave components extracted from impulse responses of a measurement signal measured at a target location, such that a vertically-directional reflected wave component and direct sound of the acoustic signals output by the speaker array overlap at the target position. 
 
     
     
       10. The method of  claim 9 , further comprising creating the reflected wave overlapping filter by performing time-reversal on the one or more extracted vertically-directional reflected wave components. 
     
     
       11. The method of  claim 10 , wherein the gain and delay values are extracted from particular impulse responses measured in a predetermined early reflection period among the measured impulse responses of the measurement signal. 
     
     
       12. The method of  claim 11 , wherein the primary filtering comprises:
 replicating the input signal by the number of the one or more vertically-directional reflected wave components extracted from the measured impulse responses to generate replicated input signals; 
 distributing the replicated input signals; 
 applying the gain and delay values of the one or more extracted vertically-directional reflected wave components to the distributed input signals, respectively; and 
 summing signals resulting from applying the gain and the delay values to the distributed input signals. 
 
     
     
       13. The method of  claim 11 , wherein the reflection wave overlapping filter comprises a Finite Impulse Response (FIR) filter designed using the gain and delay values of the one or more extracted vertically-directional reflected wave components. 
     
     
       14. The method of  claim 9 , wherein a response at the target position may be calculated according to:
   h i (t)≈Σg ij (t)*(q(−t)*f i (t)),
 
 wherein h i (t) is a first impulse response function, g ij (t) is a second impulse response function, q(−t) is a time reversed third impulse response function, f i (t) is a focusing filter, i is a channel of a speaker array, and j is the target position. 
 
     
     
       15. A method of creating an acoustic radiation pattern using a speaker array, the method comprising:
 replicating an input signal by a number of output channels of a speaker array to generate replicated signals; and 
 processing, with a filtering unit, the replicated signals to generate acoustic signals that, when output by a speaker array, have a predetermined radiation pattern in a horizontal direction within a room and a vertically-directional reflected wave component and direct sound that overlap at a target position, wherein 
 the filtering unit processes the replicated signals by applying gain and delay values of one or more vertically-directional reflected wave components extracted from impulse responses of a measurement signal measured at the target location. 
 
     
     
       16. The method of  claim 15 , wherein the filtering unit comprises a reflected wave overlapping filter that performs time-reversal on the one or more extracted vertically-directional reflection components. 
     
     
       17. The method of  claim 16 , wherein the reflected wave overlapping filter obtains the gain and delay values from particular impulse responses measured in a predetermined early reflection period among the measured impulse responses. 
     
     
       18. The method of  claim 15 , wherein a response at the target position may be calculated according to:
   h i (t)≈Σg ij (t)*(q(−t)*f i (t)),
 
 wherein h i (t) is a first impulse response function, g ij (t) is a second impulse response function, q(−t) is a time reversed third impulse response function, f i (t) is a focusing filter, i is a channel of a speaker array, and j is the target position. 
 
     
     
       19. The apparatus of  claim 1 , wherein the target position is a position where a signal reaches, and is the same for the direct sound of the input signal and the vertically-directional reflected wave component of the acoustic signals.